Women With DCIS Live Longer Than General Population

AMSTERDAM—Women diagnosed with ductal carcinoma in situ (DCIS) of the breast were found to live longer than women in the general population according to a study from the Netherlands reported at the 2017 European Cancer Congress (ECCO).

LOTTE ELSHOF speaks with Peter Goodwin at the European Cancer Congress, ECCO 2017 in AMSTERDAM

Peter Goodwin

YOU WERE LOOKING AT CAUSE SPECIFIC MORTALITY IN PATIENTS WITH DCIS, WHAT WERE YOU TRYING TO DO IN THIS STUKDY?

Lotte Elshof

We looked at patients treated for DCIS – a potential precursor lesion to invasive breast cancer and we assessed cause specific mortality. So we looked at DCIS patients and during follow up see if they had died from what cause they had died and then we compared mortality with mortality in the general population. We wanted to look at [whether] DCIS patients had increased risk of dying.

WHY DID YOU WANT TO LOOK AT DCIS?

DCIS is a potential precursor to invasive breast cancer. So some DCIS lesions will progress into invasive breast cancer and invasive breast cancer can metastasise and then cause death so it’s an important thing to look at the outcomes of DCIS and there are a lot of uncertainties and anxiety associated with DCIS because many patients diagnosed with DCIS think they are diagnosed with breast cancer. But it’s not breast cancer, yet.

TELL ME WHAT YOU DID IN THE STUDY?

We looked at patients diagnosed with DCIS between 1989 and 2004 and we looked at the causes of death in this population and we compared these observed death numbers with the expected number of deaths.

QUITE A BIG GROUP?

Yes. Almost 10 000 women with DCIS

WHAT DID YOU FIND?

We found that DCIS patients older than 50 at diagnosis were at lower risk of dying compared to the general population. And—it may sound a bit counter-intuitive—but we think it is because these patients are mostly screen-detected so they go to the population-based screening program for breast cancer and these patients are likely to be more health conscious.

DETAILS—A THREE TIMES HIGHER RISK?

We saw that DCIS patients had lower risk of dying despite their increased risk of dying from breast cancer. So if you compare the risk of dying from breast cancer to the general population we see that they have an increased risk. But then if we look at absolute numbers—the risk a woman [actually] had—then the risk is very low. So after ten years 2.5 per cent of the women died from breast cancer but compared to the general population this is only slightly increased risk.

AND YOU ALSO MENTIONED THAT THE RISK OF DEATH FROM BREAST CANCER WAS INDEPENDENT OF TREATMENT?

Yes we found that no matter what treatment the risk of mortality was so low. So we compared women treated with breast conserving therapy alone, breast conserving therapy with radiotherapy, and mastectomy and we saw no differences in breast cancer mortality.

PRACTICAL MESSAGES FOR DOCS?

This study provides accurate risk estimates—relative risks and absolute risks— which are important information to the patient. And I think these patients should be told they have a precursor lesion of invasive breast cancer but not yet invasive breast cancer and it should provide reassurance.

WHAT DOES THIS IMPLY FOR LOOKING FOR DCIS BECAUSE MANY WOMEN GET WORRIED BY THE DIAGNOSIS?

Yes. It’s a very worrying diagnosis. It’s associated with a lot of anxiety and confusion. It means that we sometimes find lesions that we would have rather not detected but because of screening we will find those lesions and the screening program also has a lot of benefits. So it’s not that we say that we don’t need to screen but there are always harms against benefits and some DCIS detection would be beneficial.

YOU DON’T WANT TO COMMIT YOURSELF WHETHER IT’S BETTER TO HAVE KNOWLEDGE OF YOUR DCIS?

No. We cannot conclude that. We need more studies. More prospective studies and also we need to wait for the prospective studies on active surveillance of DCIS because at this moment we don’t have this information.

WHAT IS THE TAKE HOME MESSAGE FOR CANCER CLINICIANS?

Accurately explain the diagnosis of DCIS. Tell the patient what it is. And these women with screen-detected DCIS can be reassured that they have the same life expectancy as other women.

ARTICLE:

Women With DCIS Live Longer Than General Population

By Peter M Goodwin

AMSTERDAM—Women diagnosed with ductal carcinoma in situ (DCIS) of the breast were found to live longer than women in the general population according to a study from the Netherlands reported at the 2017 European Cancer Congress (ECCO).

“It may sound a bit counter-intuitive—but we found that DCIS patients older than 50 at diagnosis were at lower risk of dying compared to the general population,” said Lotte Elshof, MD PhD Student Associate of the Departments of Surgery, Epidemiology and Molecular Pathology at the Netherlands Cancer Institute in Amsterdam.

“We think it is because these patients are mostly screen-detected so they go to the population-based screening program for breast cancer and are likely to be more health conscious,” she said.

The findings she reported were associated with the on-going randomized, non-inferiority phase III “LORD” trial being conducted in the Netherlands by the BOOG (Borstkanker Onderzoek Groep) team under principal investigator Jelle Wesseling MD PhD, Consultant Breast Pathologist at the Netherlands Cancer Institute in Amsterdam looking at “management of low grade ductal carcinoma in situ: active surveillance or not?” https://www.boogstudycenter.nl/studie/276/lord.html

Elshof explained that they looked at patients being treated for DCIS because it was a potential precursor lesion to invasive breast cancer.

“If [patients] had died we assessed cause-specific mortality [to] see from what cause they had died. And then we compared [their] mortality with mortality in the general population,” she said.

The study found that patients with DCIS had lower risk of dying of all causes combined compared to the general population and “seem to represent a generally healthy subgroup.”

Also, their absolute risk of breast cancer death was low—3.9 percent at 15 years—and the risk of dying from breast cancer among women treated for DCIS alone was only slightly higher than that in the general population.

The suggestion was that “a history of primary DCIS has no negative effect on overall survival.”

The study looked at 9,799 women treated for DCIS in the Netherlands from 1989 to 2004. 1,429 deaths occurred over a median follow-up of 10 years of which 368 were due to cardiovascular disease (4 percent of the total population) and 284 deaths were due to breast cancer (3 percent).

These data revealed an overall risk of dying of all causes that was significantly lower combined compared to the general population.

“There are a lot of uncertainties and anxiety associated with DCIS because many patients think they are diagnosed with breast cancer. Some DCIS lesions will progress into invasive breast cancer and can metastasize and then cause death. So it’s an important to look at the outcomes,” Elshof said.

Breast Cancer-Specific Risk

Although the study confirmed that patients with DCIS were at increased risk of dying from breast cancer they still had a lower risk of dying overall despite this.

“If we look at absolute numbers the risk is very low,” she said. “After ten years 2.5 percent of the women died from breast cancer—but compared to the general population this is only a slightly increased risk.”

Intriguingly the study also found that the risk of dying from breast cancer was independent of the type of treatment patients received.

“We found that no matter what treatment, the risk of mortality was low. We compared women treated with breast conserving therapy alone, breast conserving therapy with radiotherapy, and mastectomy. And we saw no differences in breast cancer mortality,” she said.

When she was asked what was the practical message for cancer clinicians she said the study provided accurate estimates of relative and absolute risk which she regarded as important information for the patient.

“These patients should be told they have a precursor lesion of invasive breast cancer but not yet invasive breast cancer. And it should provide reassurance,” she said.

“[DCIS is] a very worrying diagnosis. It’s associated with a lot of anxiety and confusion. It means that we sometimes find lesions that we would have rather not detected. But because of screening we find those lesions and the screening program also has a lot of benefits. So it’s not that we say we don’t need to screen but [that] there are always harms against benefits. And some DCIS detection would be beneficial,” said Elshof.

She concluded that doctors could now accurately explain the diagnosis of DCIS, and tell patients what it is and reassure them they have the same life expectancy as other women.

Philip Poortmans MD PhD, President-elect of ECCO and head of the Radiation Oncology Department at Radboud University Medical Center in Nijmegen, in The Netherlands said that although ductal carcinoma in situ should be considered as being clearly different from breast cancer treatments had side-effects.

“This research provides reassurance for women with DCIS because it shows that they are as likely to be alive ten years after the diagnosis as people in the general population who did not have DCIS. This is also reassuring with regards to the potential risks of side-effects,” he said.

“However, we have to recognize that in one fifth of patients who die, the cause is breast cancer—which is likely to result from progression of the DCIS they were diagnosed with. Therefore, we are eagerly waiting results of further research to identify factors—including age, as clearly shown in this study—that contribute to the risk for recurrence and progression from DCIS for each individual patient.”

Poortmans thought it was remarkable that the increased risk of dying from breast cancer was completely offset by a lower risk of dying from other causes compared to women in the general population.

“This might be explained by the generally better health and socioeconomic status of women who regularly participate in breast cancer screening. This could also be tested in the on-going research,” he said.